8CHLUNDT DIELECTRIC CONSTANTS OF PURE SOLVENTS. 367 



under 744. 6 mm. of pressure was used for the measurements. 

 The D. C. was found to be 12.55 at 20° C, a result which agrees 

 well with the foregoing. The settings for maximum resonance 

 were well denned. 



a-Picoline. — The sample was Schuchardt's preparation. 

 It was treated with fused calcium chloride, and redistilled. The 

 boiling point of the portion taken for the measurements was 

 128.5° — 129.5° C. at 736 mm. of pressure. The value 

 found for the D. C. is 9.8 at 20° C. 



The unpurified sample of pyridine, it will be noted, gave a 

 slightly lower D. C. than the purified sample. The former 

 very likely contained a slight amount of picoline. 



Quinoline. — Two samples of quinoline were measured. The 

 first was obtained by redistilling Schuchardt's preparation 

 marked, "Quinoline from Coal Tar." The portion which dis- 

 tilled at 232° C. under 746 mm. of pressure was measured. 

 Its D. C. was found to be 8 .7 at 22° C. 



The second sample was a synthetic preparation, made by 

 Messrs. Maxon and Thomas in this laboratory according to the 

 method of Skraup. The boiling point of the sample measured 

 was 232° C. under 746 mm. of pressure. Its dielectric constant 

 was found to be 8 . 9 at 20 . 5° C. The agreement is close enough 

 to fall within the limit of error. The absorption is slight. 

 These values of the D. C. agree well with the result, 8.9, 

 obtained by Turner 1 who worked with JSTernst's apparatus. 



Piperidine. — The sample was E. de Haen's preparation. It 

 w&s redistilled and the portion distilling between 105.5° and 

 107.0° C. under a pressure of 745 mm. was used for the meas- 

 urements. It was an almost colorless liquid and showed no ab- 

 sorption. The value found for its D. C. was 5.8 at 22° C. 



Carbon dichloride. — The sample was of Schuchardt's make. 

 Its boiling-point was 118° at 726.5 mm. of pressure. The value 

 2.46 was found for its D. C. at 21° C. 



Nitromethane. — Schuchardt's preparation was treated with 

 fused calcium chloride and redistilled. Its boiling-point was 



1 Zeit. phys. Chem. 35, 385. (1900). 



